When Theresa May took the world by surprise on Tuesday by announcing that she would seek an early general election, she said a bigger Conservative majority would strengthen her negotiating hand over Brexit.
But the outcome of two other elections this year, in France and Germany, could have almost as profound an impact on the negotiations between Britain and the European Union.
Four frontrunners are bunched closely together ahead of the first round of France’s presidential election on Sunday, and all but one is likely to create a headache for May.
Although some ultra-Brexiteers fantasise about a victory for Marine Le Pen as the next step towards the destruction of the EU, the far-right candidate would in practice be Britain's biggest nightmare.
Although she has not called explicitly for France to leave the EU, her entire policy programme of immigration control and economic protectionism is incompatible with continued membership.
Mélenchon could prove almost as disruptive to the Brexit process as Le Pen
A Le Pen presidency would tip the EU into crisis, eating up much of the already scarce organisational bandwidth available for negotiating a mutually satisfactory deal with Britain.
The same is true of Jean-Luc Mélenchon, the far-left candidate who abhors Le Pen’s views on immigration but shares her hostility to the EU, which he views as an engine of globalisation and economic austerity.
Although he is the only candidate to mention Brexit in his manifesto, calling for a deal which does not punish Britain, Mélenchon could prove almost as disruptive to the Brexit process as Le Pen.
Opposite problem
Emmanuel Macron, the candidate of the centre and an ardent advocate of European integration, presents the opposite problem as Mélenchon and Le Pen.
His priority in the Brexit negotiations is to strengthen the EU and he made clear during a visit to London in February that he will oppose any exceptions or special arrangements for Britain after it leaves.
Britain’s preferred candidate is François Fillon, a conservative who opposed the Maastricht Treaty and favours a greater role for national governments in the EU.
He wants to renegotiate the EU treaties to return powers to the member-states and he is sympathetic to the views of some British Eurosceptics. To top it all, his wife is Welsh.
British officials have long cherished the hope that, if Brexit negotiations start to go badly, German chancellor Angela Merkel will intervene on Britain's behalf, egged on by her country's industrialists.
Merkel’s position towards Britain has hardened in recent months, however, as she fears that too soft a deal could undermine the EU.
Merkel's room for manoeuvre is further limited by the strength of Social Democrat Martin Schultz's challenge
Berlin is deeply unsympathetic to Britain’s wish to negotiate downwards the cost of its outstanding liabilities as it leaves the EU, because Germany might have to make up the financial shortfall.
German industry has also concluded that a strong EU should take priority over the imperative to continue trading without barriers with Britain.
Schulz challenge
Merkel’s room for manoeuvre is further limited by the strength of Social Democrat Martin Schultz’s challenge ahead of September’s election.
As president of the European Parliament, Schultz greeted last year's referendum result with a call for Britain to start the process of getting out of the EU as quickly as possible.
He is likely to resist any compromise with Britain that could undermine the integrity of the EU more fiercely than Merkel.
Victory in June’s election could offer May greater scope to disappoint hardline Brexiteers on the Conservative backbenches and the early election has bought the British government an extra two years between the end of article 50 negotiations and its next rendezvous with the voters.
But promises made during the campaign could serve to limit May’s capacity to compromise in the negotiations.
On Thursday, May’s campaign was forced to confirm that she remained committed to reducing net immigration to below 100,000, an arbitrary target which makes no economic sense.
And the Daily Mail reported that her promise to end free movement and withdraw from the single market and the European Court of Justice would be included in the Conservative manifesto.
The election will do nothing to resolve the prime minister’s central difficulty in the negotiations: the fact that 90 per cent of Conservative voters want to end free movement while continuing to trade with the EU as freely as today, which EU negotiators say is impossible.